CRTAC1 Gene

Name	cartilage acidic protein 1
Description	This gene encodes a glycosylated extracellular matrix protein that is found in the interterritorial matrix of articular deep zone cartilage. This protein is used as a marker to distinguish chondrocytes from osteoblasts and mesenchymal stem cells in culture. The presence of FG-GAP motifs and an RGD integrin-binding motif suggests that this protein may be involved in cell-cell or cell-matrix interactions. Copy number alterations in this gene have been observed in neurofibromatosis type 1-associated glomus tumors. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2011]
Summary	{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Cartilage acidic protein 1 (CRTAC1) is emerging as a multifunctional extracellular matrix protein with diverse roles in tissue homeostasis, disease biomarker development, and cell signaling. Initially identified as a chondrocyte‐specific marker, CRTAC1 is expressed in articular cartilage where alternative splicing produces a glycosylated isoform (CRTAC1‐A) that likely functions in cell–cell and cell–matrix interactions and in extracellular matrix (ECM) organization, differentiation, and remodeling."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In osteoarthritis, plasma CRTAC1 levels are strongly associated with disease diagnosis and progression to joint replacement, underscoring its promise as a minimally invasive biomarker of cartilage degeneration."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In the ocular system, CRTAC1 plays a role in mediating the response of human lens epithelial cells to ultraviolet B (UVB) irradiation. Experimental knockdown of CRTAC1 in these cells reduces reactive oxygen species production, intracellular calcium overload, and subsequent apoptosis as well as pyroptosis, suggesting that CRTAC1 contributes to oxidative stress‐induced cell death and may represent a novel target for cataract treatment."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "3", "end_ref": "5"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Structural analyses reveal that CRTAC1 contains multiple FG–GAP repeat domains and an RGD integrin-binding motif, forming a beta-propeller architecture that is evolutionarily conserved. This structure not only supports its function in mediating cell adhesion but also confers a propensity to form high molecular weight, amyloid-like aggregates that may underlie its involvement in disease processes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Beyond cartilage and lens tissue, CRTAC1 also impacts cellular behaviors in other contexts. In bladder cancer, CRTAC1 is downregulated, and its restoration suppresses cell viability, proliferation, migration, invasion, and epithelial–mesenchymal transition by targeting transcription factors and inactivating the transforming growth factor–β pathway, suggesting a tumor-suppressive role."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": " Similarly, in primary human dermal fibroblasts, recombinant CRTAC1‐A stimulates cell proliferation, migration, and ECM production, implicating it in wound healing and tissue repair processes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, CRTAC1 expression is widely used as a marker of chondrocyte differentiation in stem cell-based tissue engineering, further emphasizing its central role in maintaining tissue-specific phenotypes. Notably, its inclusion in multi-gene prognostic signatures for conditions such as lower-grade glioma supports an extended role in tumor biology and intercellular signaling."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In summary, CRTAC1 functions as a key extracellular matrix molecule involved in cellular adhesion, differentiation, and proliferation, with additional roles in modulating oxidative stress–related apoptosis and pyroptosis. Its altered expression in diverse pathological conditions—including osteoarthritis, cataract formation, and various cancers—positions CRTAC1 as both a valuable biomarker and a potential therapeutic target.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Eric Steck, Jessica Bräun, Karoliina Pelttari, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Chondrocyte secreted CRTAC1: a glycosylated extracellular matrix molecule of human articular cartilage."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Matrix Biol (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.matbio.2006.09.006"}], "href": "https://doi.org/10.1016/j.matbio.2006.09.006"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17074475"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17074475"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Unnur Styrkarsdottir, Sigrun H Lund, Saedis Saevarsdottir, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The CRTAC1 Protein in Plasma Is Associated With Osteoarthritis and Predicts Progression to Joint Replacement: A Large-Scale Proteomics Scan in Iceland."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Arthritis Rheumatol (2021)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/art.41793"}], "href": "https://doi.org/10.1002/art.41793"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "33982893"}], "href": "https://pubmed.ncbi.nlm.nih.gov/33982893"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Yinghong Ji, Xianfang Rong, Dan Li, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Inhibition of Cartilage Acidic Protein 1 Reduces Ultraviolet B Irradiation Induced-Apoptosis through P38 Mitogen-Activated Protein Kinase and Jun Amino-Terminal Kinase Pathways."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cell Physiol Biochem (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1159/000447920"}], "href": "https://doi.org/10.1159/000447920"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27855397"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27855397"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Yang Sun, Xianfang Rong, Dan Li, et al. "}, {"type": "b", "children": [{"type": "t", "text": "NF-κB/Cartilage Acidic Protein 1 Promotes Ultraviolet B Irradiation-Induced Apoptosis of Human Lens Epithelial Cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "DNA Cell Biol (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1089/dna.2019.5086"}], "href": "https://doi.org/10.1089/dna.2019.5086"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "31999475"}], "href": "https://pubmed.ncbi.nlm.nih.gov/31999475"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Yang Sun, Xianfang Rong, Dan Li, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Down-regulation of CRTAC1 attenuates UVB-induced pyroptosis in HLECs through inhibiting ROS production."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochem Biophys Res Commun (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.bbrc.2020.07.028"}], "href": "https://doi.org/10.1016/j.bbrc.2020.07.028"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "32838966"}], "href": "https://pubmed.ncbi.nlm.nih.gov/32838966"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Liliana Anjos, Isabel Morgado, Marta Guerreiro, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Cartilage acidic protein 1, a new member of the beta-propeller protein family with amyloid propensity."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proteins (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/prot.25210"}], "href": "https://doi.org/10.1002/prot.25210"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27862299"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27862299"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "Jianghua Yang, Li Fan, Xiaoxing Liao, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CRTAC1 (Cartilage acidic protein 1) inhibits cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) process in bladder cancer by downregulating Yin Yang 1 (YY1) to inactivate the TGF-β pathway."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Bioengineered (2021)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1080/21655979.2021.1974645"}], "href": "https://doi.org/10.1080/21655979.2021.1974645"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "34818994"}], "href": "https://pubmed.ncbi.nlm.nih.gov/34818994"}]}, {"type": "r", "ref": 8, "children": [{"type": "t", "text": "Sophia Letsiou, Rute C Félix, João C R Cardoso, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Cartilage acidic protein 1 promotes increased cell viability, cell proliferation and energy metabolism in primary human dermal fibroblasts."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochimie (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.biochi.2020.02.008"}], "href": "https://doi.org/10.1016/j.biochi.2020.02.008"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "32084494"}], "href": "https://pubmed.ncbi.nlm.nih.gov/32084494"}]}, {"type": "r", "ref": 9, "children": [{"type": "t", "text": "Sophia Letsiou, Manuel Manchado, Mariela Zografaki, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Deciphering the role of cartilage protein 1 in human dermal fibroblasts: a transcriptomic approach."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Funct Integr Genomics (2021)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1007/s10142-021-00792-x"}], "href": "https://doi.org/10.1007/s10142-021-00792-x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "34269961"}], "href": "https://pubmed.ncbi.nlm.nih.gov/34269961"}]}, {"type": "r", "ref": 10, "children": [{"type": "t", "text": "Begoña Redruello, Bruno Louro, Liliana Anjos, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CRTAC1 homolog proteins are conserved from cyanobacteria to man and secreted by the teleost fish pituitary gland."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Gene (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.gene.2010.02.003"}], "href": "https://doi.org/10.1016/j.gene.2010.02.003"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20171266"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20171266"}]}, {"type": "r", "ref": 11, "children": [{"type": "t", "text": "Kai Xiao, Qing Liu, Gang Peng, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification and validation of a three-gene signature as a candidate prognostic biomarker for lower grade glioma."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PeerJ (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.7717/peerj.8312"}], "href": "https://doi.org/10.7717/peerj.8312"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "31921517"}], "href": "https://pubmed.ncbi.nlm.nih.gov/31921517"}]}]}]}
Synonyms	CEP-68, ASPIC, CEP68, LOTUS, ASPIC1
Proteins	CRAC1_HUMAN
NCBI Gene ID	55118
API
Download Associations
Predicted Functions
Co-expressed Genes
Expression in Tissues and Cell Lines

Functional Associations

CRTAC1 has 5,155 functional associations with biological entities spanning 9 categories (molecular profile, organism, chemical, functional term, phrase or reference, disease, phenotype or trait, structural feature, cell line, cell type or tissue, gene, protein or microRNA, sequence feature) extracted from 114 datasets.

Click the + buttons to view associations for CRTAC1 from the datasets below.

If available, associations are ranked by standardized value

Harmonizome 3.0

CRTAC1 Gene

Functional Associations

Please acknowledge the Harmonizome in your publications by citing the following reference(s):

	Dataset	Summary
	Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CRTAC1 gene relative to other tissues from the Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles	tissues with high or low expression of CRTAC1 gene relative to other tissues from the Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles	tissue samples with high or low expression of CRTAC1 gene relative to other tissue samples from the Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray	tissue samples with high or low expression of CRTAC1 gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq	tissue samples with high or low expression of CRTAC1 gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq dataset.
	Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CRTAC1 gene relative to other tissues from the Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles dataset.
	BioGPS Cell Line Gene Expression Profiles	cell lines with high or low expression of CRTAC1 gene relative to other cell lines from the BioGPS Cell Line Gene Expression Profiles dataset.
	BioGPS Human Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CRTAC1 gene relative to other cell types and tissues from the BioGPS Human Cell Type and Tissue Gene Expression Profiles dataset.
	BioGPS Mouse Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CRTAC1 gene relative to other cell types and tissues from the BioGPS Mouse Cell Type and Tissue Gene Expression Profiles dataset.
	Carcinogenome Chemical Perturbation Carcinogenicity Signatures	small molecule perturbations changing expression of CRTAC1 gene from the Carcinogenome Chemical Perturbation Carcinogenicity Signatures dataset.
	CCLE Cell Line Gene CNV Profiles	cell lines with high or low copy number of CRTAC1 gene relative to other cell lines from the CCLE Cell Line Gene CNV Profiles dataset.
	CCLE Cell Line Gene Expression Profiles	cell lines with high or low expression of CRTAC1 gene relative to other cell lines from the CCLE Cell Line Gene Expression Profiles dataset.
	CellMarker Gene-Cell Type Associations	cell types associated with CRTAC1 gene from the CellMarker Gene-Cell Type Associations dataset.
	ChEA Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CRTAC1 gene from the CHEA Transcription Factor Binding Site Profiles dataset.
	ChEA Transcription Factor Targets	transcription factors binding the promoter of CRTAC1 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets dataset.
	ChEA Transcription Factor Targets 2022	transcription factors binding the promoter of CRTAC1 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets 2022 dataset.
	CM4AI KOLF21J CRISPRi Gene Perturbation Atlas	gene perturbations changing expression of CRTAC1 gene from the CM4AI KOLF21J CRISPRi Gene Perturbation Atlas dataset.
	CMAP Signatures of Differentially Expressed Genes for Small Molecules	small molecule perturbations changing expression of CRTAC1 gene from the CMAP Signatures of Differentially Expressed Genes for Small Molecules dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores	cellular components containing CRTAC1 protein from the COMPARTMENTS Curated Protein Localization Evidence Scores dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores 2025	cellular components containing CRTAC1 protein from the COMPARTMENTS Curated Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Experimental Protein Localization Evidence Scores 2025	cellular components containing CRTAC1 protein in low- or high-throughput protein localization assays from the COMPARTMENTS Experimental Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores	cellular components co-occuring with CRTAC1 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025	cellular components co-occuring with CRTAC1 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025 dataset.
	COSMIC Cell Line Gene Mutation Profiles	cell lines with CRTAC1 gene mutations from the COSMIC Cell Line Gene Mutation Profiles dataset.
	CTD Gene-Chemical Interactions	chemicals interacting with CRTAC1 gene/protein from the curated CTD Gene-Chemical Interactions dataset.
	CTD Gene-Disease Associations	diseases associated with CRTAC1 gene/protein from the curated CTD Gene-Disease Associations dataset.
	dbGAP Gene-Trait Associations	traits associated with CRTAC1 gene in GWAS and other genetic association datasets from the dbGAP Gene-Trait Associations dataset.
	DepMap CRISPR Gene Dependency	cell lines with fitness changed by CRTAC1 gene knockdown relative to other cell lines from the DepMap CRISPR Gene Dependency dataset.
	DISEASES Experimental Gene-Disease Association Evidence Scores	diseases associated with CRTAC1 gene in GWAS datasets from the DISEASES Experimental Gene-Disease Assocation Evidence Scores dataset.
	DISEASES Experimental Gene-Disease Association Evidence Scores 2025	diseases associated with CRTAC1 gene in GWAS datasets from the DISEASES Experimental Gene-Disease Assocation Evidence Scores 2025 dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores	diseases co-occuring with CRTAC1 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores 2025	diseases co-occuring with CRTAC1 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores 2025 dataset.
	DisGeNET Gene-Disease Associations	diseases associated with CRTAC1 gene in GWAS and other genetic association datasets from the DisGeNET Gene-Disease Associations dataset.
	DisGeNET Gene-Phenotype Associations	phenotypes associated with CRTAC1 gene in GWAS and other genetic association datasets from the DisGeNET Gene-Phenoptype Associations dataset.
	ENCODE Histone Modification Site Profiles	histone modification site profiles with high histone modification abundance at CRTAC1 gene from the ENCODE Histone Modification Site Profiles dataset.
	ENCODE Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CRTAC1 gene from the ENCODE Transcription Factor Binding Site Profiles dataset.
	ENCODE Transcription Factor Targets	transcription factors binding the promoter of CRTAC1 gene in ChIP-seq datasets from the ENCODE Transcription Factor Targets dataset.
	ESCAPE Omics Signatures of Genes and Proteins for Stem Cells	PubMedIDs of publications reporting gene signatures containing CRTAC1 from the ESCAPE Omics Signatures of Genes and Proteins for Stem Cells dataset.
	GAD Gene-Disease Associations	diseases associated with CRTAC1 gene in GWAS and other genetic association datasets from the GAD Gene-Disease Associations dataset.
	GAD High Level Gene-Disease Associations	diseases associated with CRTAC1 gene in GWAS and other genetic association datasets from the GAD High Level Gene-Disease Associations dataset.